cap knife

I hate washing out a knife every time I need condiments, even penut butter and jelly. Why cant they make a knife built into the cap you dont need to wash it off cause it will be going right back into the same jar. It could be plastic or metal. Remeber the paste jars in school, it would be exactly like that. I know there is squeezable stuff out, but still there is alot of stuff that comes in jars. For pickle jars put a fork instead of a knife. Less dirty dishes and a time saver! I want part of the money if someone takes this idea, I'm getting sick of eating pb&j sandwiches:-)